So Sigma has the nerve to make a faster than F/2.8 zoom and they make it for APS-C?!.

Someone help me understand the market target for such a lens. After all, I thought the people buying high end glass for their APS-C rigs are 7D users buying long primes for birding. What APS-C users have been lamenting that their 17-55 F/2.8 IS isn't quick enough? I would argue that as cool as such a new lens might be to use, this can't be a massive gap in the APS-C users' bag, right?

So it's 18-35 f/1.8 for APS-C, making at a FF-equivalent of 29-56 f/2.9Comparing, say, a 7D + this Sigma 18-35 f/1.8 to an FF, say 5D3 + 24-70 f/2.8, you get a lot more at the long end, and a bit more at the wide end.Not sure which one would combo will deliver better IQ (especially seeing how good the new 24-70 II is, it'll be hard to beat), but I can tell you which combo is going to be a lot lighter on the wallet...

Someone help me understand the market target for such a lens. After all, I thought the people buying high end glass for their APS-C rigs are 7D users buying long primes for birding. What APS-C users have been lamenting that their 17-55 F/2.8 IS isn't quick enough? I would argue that as cool as such a new lens might be to use, this can't be a massive gap in the APS-C users' bag, right?

So so so confused. Help me make sense of this, thx.

- A

A lot will depend on the price point and actual IQ of course.

I see it as a travel lens. While there are many good standard zooms on APSC, many times I felt like I needed a fast prime too for portraits and subject isolation. This lens kind of fills that gap - please also note the 28cm MFD.